Am Saturday 07 May 2016
schrieb Marc Joliet <marcec@gmx.de>

>I'm thinking of filing 
>a bug report with dovecot; perhaps none of their devs test with btrfs?

So I did this, and got a little bit of feedback.  Quoting from the reply I 
got:

"*.index.log files are always appended to using O_APPEND flag. Maybe this is 
relevant.

Also when a new .log file is created it's opened without the O_APPEND flag and 
the O_APPEND is added later. This was causing a bug recently in unionfs, which 
ignored the flag change and caused log file corruption."

The other bit of advise was to stress test dovecot using imaptest, but I'll 
have to do that when I have more time.

Greetings
-- 
Marc Joliet
--
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup